These are blowing engines number six and seven. These are single engines, meaning there is one flywheel per set of tandem cylinders. These engines were built circa 1911 using a design stolen from the Germans. Bethlehem engineers visited German plants during the day, then drew up plans in their hotel rooms at night. Technical journals refer to the engines as being of the Nuremberg type because of their origins in that German city. Extremely efficient (the twin engines reached 50 percent efficiency when combined with waste heat boilers - which were fueled by the exhaust heat of the engines), these engines ran until 1993 when an explosion in the blast air piping shuttered the powerhouse. Steam powered turbo blowers provided the blast air to the blast furnaces until the last furnace was blown out on November 18, 1995.

Photograph taken in 2009 at the abandoned Bethlehem Steel complex in Bethlehem PA by Matthew Christopher of Abandoned America. The Bethlehem Steel site has since been incorporated into the Steel Stacks and Sands Casino.